In February 1983, Bell announced the both commercial and military, single and twin-engined, Model 400 TwinRanger. This seven-seat aircraft was in the 1800-2700kg gross weight class. The Model 400 was powered by two 443shp Allison 250-C20R turboshaft engines, had a four-blade soft-in-plane main rotor, an advanced technology transmission and drive system with 'run-dry' capability.
The aircraft entered development in 1983 with wind-tunnel testing with a one-quarter scale model and flight testing of the dynamic components on a specially modified Model 206LM LongRanger (c/n 45003, N206N) which served as test-bed and flew in March 1983. This aircraft had the four-bladed OH-58D AHIP rotor, a strengthened tail boom, a ring guard tail rotor and a deepened fuselage to increase fuel capacity.
The first prototype Model 400 (c/n 48001, N3185K) flew on 30 June, 1984, powered by Allison engines.
Three pre-production Model 400 TwinRangers (c/n 48002/ 48004) were built, the first of which (N3185L) flew for the first time on 4 July, 1985, the second (N3185U) in May and the third (N400BH) in June 1985. The first aircraft was later used as a ground test vehicle.
It was expected that the Canadian factory, at Mirabel, Montreal, would undertake production of the Model 400 and develop the Model 400A, a variant of the Model 400 powered by a single 1000shp Pratt & Whitney Canada PW209T turboshaft engine, and employing major composites components.
The programme was suspended indefinitely pending a market situation that would support an annual sales rate of about 120 aircraft. The four existing aircraft have been cancelled from the register and put in storage by Bell Helicopter Textron Canada, at Mirabel.
Rotor diameter: 11.30m
Overall length: 13.39m
Length of fuselage: 11.02m
Height overall: 3.56m
Maximum take-off weight: 2495kg
Empty weight: 1427kg
Maximum speed: 278km/h
Maximum cruising speed at 1525m: 244km/h
Initial rate of climb: 464m/min
Service ceiling: 6100m
Hover ceiling outside ground effect: 3110m
Hover ceiling in ground effect: 4360m
Maximum range: 834km